Hydraulic press with pulsating load

ABSTRACT

A press provided with a power cylinder in which a space located above the piston for the working stroke of the latter is connected to a high pressure main and through a pulsator to a drain pipe and a space located under the piston for its return to the initial position is connected to a high pressure main through a throttle, high pressure accumulator and a one-way valve arranged in a consecutive order. Such a connection of the space under the piston to the high pressure main makes it possible to control the amplitude of the piston oscillation enabling the press to be used for different operations of metal pressure shaping.

United States atent r191 Deordiev et al.

[451 Feb. 4, 1975 HYDRAULIC PRESS WITH PULSATHNG LOAD [76] Inventors: Nikolai Trifonovich Deordiev, ulitsa Fridrikha Engelsa, 42, kv. 40; Ivan Vasilievich Kononov, ulitsa Torpedo, 40, kv. 4; Ivan Egorovich Maslennikov, ulitsa Druzhinnikov 26, kv. 82; Gennady Vitalievich Modzheevsky, ulitsa Koltsovskaya 82, kv. 35; Vladimir Niklforovich Platonov, ulitsa 9 Yanvarya 49, kv. 45; Vasily Tikhonovich Sukhanov, Bulvar Pionerov 20, kv. 73, all of Veronezh, U.S.S.R.

[22 Filed: July 10, 1973 21 App]. No.: 377,911

[52] US. Cl. 72/453 [51] Int. Cl B21j 9/12 [58] Field of Search 72/453; 100/269 R [56] References Cited UNITED STATES PATENTS Hirst 72/453 3,173,286 3/1965 Dischler 72/453 3,416,354 l2/l968 Fisher 72/453 Primary Examiner-C. W. Lanham Assistant Examiner-Gene P. Crosby Attorney, Agent, or Firm-Holman & Stern [57] ABSTRACT A press provided with a power cylinder in which a space located above the piston for the working stroke of the latter is connected to a high pressure main and through a pulsator to a drain pipe and a space located under the piston for its return to the initial position is connected to a high pressure main through a throttle, high pressure accumulator and a one-way valve arranged in a consecutive order.

Such a connection of the space under the piston to the high pressure main makes it possible to control the amplitude of the piston oscillation enabling the press to be used for different operations of metal pressure shaping.

1 Claim, 1 Drawing Figure HYDRAULIC PRESS WITH PULSATING LOAD BACKGROUND OF THE INVENTION The present invention relates to metal pressure shaping and more particularly to hydraulic presses with a pulsating load.

It is most advantageous for the present hydraulic press to be used for the manufacture of stepped shafts of different sections, reducing and calibration of pipes and shapes.

It is also advantageous to use the hydraulic press for stretching, cleaning, caulking and pressing of powders of different materials.

PRIOR ART Known in the art is a hydraulic press with a pulsating load in which a space of the power cylinder arranged above the piston for the working stroke of the latter is connected to a high pressure main and through a pulsator to a drain pipe. Another space arranged under the piston and serving for the return of the latter to the initial position is connected through a one-way valve to a high pressure main.

In this embodiment, the amplitude of the piston oscillation (stroke of piston for each cycle) is in ratio with the power accumulated in the space under the piston by compression of the liquid. The more the volume of the space and pressure of the liquid, the more power is accumulated therein. In its turn, pressure under the piston is in ratio with the pressure in the space above the piston.

In the process of operation, pressure in the space above the piston varies with the required technological effort and therefore pressure in the space under the piston and accordingly the amplitude of the piston oscillation also varied with this effort. However many techno logical processes e.g., stretching, cleaning, calibration of pipes and shapes, etc., with the increase of resistance of deformation or with a change of effort on the piston require a stable amplitude of piston oscillation.

The above hydraulic press with a pulsating load provides no control of the amplitude of piston oscillation which limits its technological possibilities.

OBJECTS AND SUMMARY OF THE INVENTION An object of the present invention is to provide a press with a pulsating load with an independent control of the amplitude of piston oscillation which enables the press to be used for different processes of metal pressure shaping.

The above and other objects are accomplished in that in a hydraulic press with a pulsating load in which a space of a power cylinder arranged above a piston for the working stroke of the latter is connected to a high pressure main and through a pulsator to a drain pipe and a space arranged under the piston is connected through a one-way valve to the high pressure main for return of the piston to the initial position, according to the invention, on the main connecting the space under the piston to the one-way valve, a throttle and a high pressure accumulator are arranged in consecutive order thus enabling the control of the amplitude of the piston oscillation.

A hydraulic press with a pulsating load according to the present invention makes it possible to control the amplitude of the piston oscillation at different technological processes and to improve the quality of shaping accordingly.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood from the following description of its specific embodiment taken in conjunction with the accompanying drawing in which the sole FIGURE illustrates a longitudinal sectional schematic view to a hydraulic press with a pulsating load, according to the invention.

DETAILED DESCRIPTION OF THE INVENTION The press comprises a bed I, in which a cylinder 2 is housed. The cylinder accommodates a piston 3 forming in conjunction with the latter a power cylinder.

On the bed 1, a table 4 is fixed and a die 5 is mounted on the table. In the cylinder 2, a space or chamber 610- cated above the piston 3 is referred hereinafter as the above-piston space and a space or chamber 7 located under the piston 3 as the under-piston space.

For the working stroke of the piston 3, the abovepiston-space 6 is connected through a pipeline 8 to a high pressure main 9 and to take offa load from the piston 3, said space 6 is connected through a pulsator 10 to a drain pipe 11.

The pulsator 10 is provided with a casing 12 in which a loading valve 13 is housed and is designed for closing the high pressure main 9 during the working stroke of the piston 3 and for connection ofthis main to the drain pipe 11 when the pressure drops in the above-piston space 6.

Coaxially with the valve, the casing 12 houses a pusher l4, pressed onto the valve 13 by a spring 15 and a piston 16 adapted to create an effort on the valve 13. Between the valve I3 and the pusher 14, a space or chamber 17 is located which is a part of the high pressure main 9.

Under the pusher I4, a space or chamber 18 is located which is connected through a one-way valve 19 and a throttle 20 connected in parallel therewith to the high pressure main 9. A space or chamber 21 formed around the cylindrical surface of the valve 13 is connected to the drain pipe II.

A space or chamber 22 located above the piston 16 is designed for the supply of compressed air thereto and is connected through an air distributor 23, a one-way valve 24 and a reducing valve 25 to a pneumatic line 26.

The under-piston space 7 serves for the return of the piston 3 to the initial position after the working stroke and for which purpose said space is connected through a throttle 27, a high pressure accumulator 28 and a one-way valve 29 to a high pressure main 30. Additionally, the accumulator 28 for being filed with gas is connected through a one-way valve 31 to a main 32. The connection of the under-piston space 7 through the throttle and accumulator to the high pressure main makes it possible to control the proportioning of the liquid while supplying the liquid to this space and thus to obtain the definite amplitude of oscillation of the piston 3 as required by technological conditions of shaping.

To control the pressure in the main 30, the latter is provided with a relief valve 33 and a contact pressure gauge 34. Supply of liquid to high pressure mains 9 and 30 is effected by means of pumps 35 and 36.

The present hydraulic press with a pulsating load operates as follows:

The pump 36 operates to supply liquid to the high pressure main 30 and through the one-way valve 29, accumulator 28 and throttle 27 to the under-piston space 7 of the cylinder 2. Prior thereto, the accumulator 28 is filled with gas, e.g., nitrogen from the main 32 through the one-way valve 31. After the pressure reaches the necessary value, the pump 36 is switched off automatically by the signal from the contact pressure gauge 34 and the pressure of liquid is retained by one-way valves 29 and 31.

The pump 35 operates to supply liquid to the high pressure main 9. If there is no effort on the piston 16, the liquid through the loading valve 13 easily flows through the space 21 to the drain pipe 11.

To start the press, it is necessary to supply compressed air from the pneumatic line 26 through the reducing valve 25, one-way valve 24 and air distributor 23 to the chamber 22 for the purpose of creating an effort on the piston 16 and the loading valve 13. Then, the liquid from the high pressure main 9 will enter the chamber 17, above-piston space 6 and through the oneway valve 19 enter the chamber 18. The piston 3 lowers down until contact with a blank (to the stop of the die and pressure in the system starts rising to a value corresponding to the effort acting downward on the loading valve 13. Up to the moment of opening of this valve, the pusher 14 is balanced by the action of liquid pressure. As pressure rises in the hydraulic system, the valve 13 partially opens due to which the excess of pressure relieves from spaces 6 and 17 and the main 9. The balance of the pusher 14 is lost and through the drop of pressure between the spaces 17 and 18 effected by the one-way valve 19 and throttle 20, the pusher l4 raises the valve 13 until the effort of the pusher downward (summary effort of the spring and remaining liquid pressure in the space 18) and the effort on the piston 16 are similar. For this period pressure in the above-piston space 6 is relieved completely. Then the piston 3 under pressure in the under-piston space 7 breaks away from the blank by the value determined by the setting of the throttle 27. From the moment the effort under the pusher 14 is lower than the effort of the piston 16, the valve 13 lowers down to its seat pressing the liquid by the pusher 14 out of the space 18 through the throttle 20. Then, the process is repeated. In such a manner in the above-piston chamber 6, pressure is formed and relieved which results in a pulsating load on the piston 3. In the process of operation, the pump 36 is periodically switched on, for instance, in the case of leakage of the liquid from the under-piston space 7 or for some other reasons. The under-piston space 7 is protected against overload by the relief valve 33.

The effort of the press is controlled by the change of air pressure in the space 22 with the reducing valve 25, and the frequency of the oscillation is controlled by the change of liquid supply from the pump and the opening of the throttle 20. The amplitude of the oscillation of the piston 3 is adjusted as required by the technological conditions of shaping. The adjustment is effected by the throttle 27 through the change of its opening irrespective of efforts on the piston 3 (or pressure in the above-piston chamber 6).

Independent control of the amplitude of the piston oscillation within a wide range makes it possible to choose the required conditions of processing and thus ensure the required quality during the whole cycle of operation.

What is claimed is:

l. A hydraulic press with a pulsating load comprising a bed, a power cylinder provided with a piston; said cylinder being arranged on said bed and having abovepiston and under-piston spaces; a source of liquid high pressure; a drain; a pulsator serving for the creation of a pulsating load in said power cylinder; said abovepiston space serving for the working stroke of the piston being connected to the said source of the liquid high pressure and through said pulsator to the drain; a pipeline connecting said under-piston space to a source ofliquid high pressure serving for the return of said piston to its initial position; a one-way valve mounted on said pipe-line; and a throttle and high pressure accumulator arranged in consecutive order on said pipeline between said under-piston space and said one-way valve enabling the control of the amplitude of oscillation of said piston. 

1. A hydraulic press with a pulsating load comprising a bed, a power cylinder provided with a piston; said cylinder being arranged on said bed and having above-piston and under-piston spaces; a source of liquid high pressure; a drain; a pulsator serving for the creation of a pulsating load in said power cylinder; said above-piston space serving for the working stroke of the piston being connected to the said source of the liquid high pressure and through said pulsator to the drain; a pipeline connecting said under-piston space to a source of liquid high pressure serving for the return of said piston to its initial position; a one-way valve mounted on said piPe-line; and a throttle and high pressure accumulator arranged in consecutive order on said pipeline between said under-piston space and said one-way valve enabling the control of the amplitude of oscillation of said piston. 